Grinding machine for internal threads



Oct. 22. 1940. F. TURRETTINI GRINDING MACHINE FOR INTERNAL THREADS Filed Dec. 14, 1938 3 Sheets-Sheet l II- nu "e/ZQM' hVea/an M Oct. 22, 1940. F. TURRETTlNl 2,218,775

GRINDING MACHINE FOR INTERNAL THREADS Filed Dec. 14, 1938 3 Sheets-Sheet 2 27 J0 T 18 a J g; a

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GRINDING MACHINE FOR INTERNAL THREADS Filed Dec. 14, 1938 3 Sheets-Sheet 3 Patented Oct. 22, 1940 UNITED STATES GRINDING MACHINE FOR INTERNAL 'rnncans Fernand Turrettini, Bellevue-Geneva, Switzerland, assignors to Socit Genevoise dlnstruments de Physique, Geneva, Switzerland, a firm of Switzerland Application December 14, 1938, Serial No. 245,786 In Switzerland December 20, 1937 2 Claims.

This invention relates to new and useful improvements in grinding machines and is directed Another object of the invention is to provide a "P trueing device which is pivotally mounted on the body of the grinding machine, whereby said trueing device may be quickly brought into trueing position without necessitating dismantling of any of the parts of the grinding machine.

A further object of the inventionresides in a pivotal mounting for the trueing device which serves not only to swing the trueing device from an inoperative position on the grinding machine to an operative position, but also to move said w device in a plane perpendicular to the plane of said swinging device, for advancing the latter toward the grinding wheel.

A still further object of the invention is to provide a pivotal connection for the trueing device which is disposed at right angles to the axis of rotation of said grinding wheel, whereby said trueing device may be readily swung into and out of operative position.

With the above and other objects in view which will appear as the description proceeds, my invention resides in the novel features hereinafter set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views.

Fig. 1 is a top plan view of the trueing device mounted on the grinding machine with the latter shown partly in section to illustrate the pivotal support for the trueing device.

Fig. 2 is a side elevation of the grinding machine with the trueing device in trueing position, the work piece having the internal threads being shown in section.

Fig. 3 is a fragmentary view showing the trueing device in trueing position on the grinding wheel.

Fig. 4 is a view similar to Fig. 2 but showing the trueing device in inoperative position on the grinding machine, and

Fig. 5 is a vertical sectional view through the trueing device.

In the drawings, I represents a wheel of any suitable abrasive material on the end of a shaft rotatable in a bearing member 2 formed in the grinding machine body 3, said wheel being adapted to grind the internal threads in a work piece A as shown in Figs. 2 and 4. A pair of horizontally spaced bearing legs I and 8 extend upwardly from the body member 3 and rotatably support at their upper ends a transverse shaft l0. As clearly shown in Fig. 1, the shaft 10 is internally drilled longitudinally from one end to a predetermined point for receiving a micrometer pin, the inner end of which is reduced and threaded as at all to cooperate with the complementary threads in a nut l3 which is adapted to slide longitudinally in a pair of longitudinal slots [4 in the shaft Ill. The outer end of the pin terminates in a knob l2 and reading drum having thereon a series of graduations for determining the exact degree of displacement of the nut l3.

A collar 5 provided on one end of an arm 4 slidably embraces the shaft l0, said collar being suitably connected to the nut I3 and movable therewith upon rotation of the pin i l. The other end of the arm 4 terminates in a transverse hollow cylinder 6 which is provided on its upper portion with an annular outwardly extending flange 6a. A tubular bracket member l6 concentric with the cylinder 6 is rotatably mounted in the latter, being supported therein by means of an annular outwardly extending flange l6a on the member I6 cooperating with a complementary annular recess on the inner periphery of the cylinder 6 adjacent accommodates a rockable spider 35 pivotally mounted by means of two short transverse pins l1 which extend outwardly from the sides of the spider and are supported in suitable bearings in member i6. An arm I 9 is suitably secured to the spider and extends downwardly from the latter, terminating at its free end in a holder for a trueing diamond 2|. The diamond is suitably supported in the holder 20 whereby it can be adjusted therein with respect to the grinding wheel I, a graduated rotatable knob 22 being provided for determining the exact adjustment of the diamond 2| as best seen in Fig. 3.

Referring to Fig. '5, numeral 32 represents a vertical plunger slidably mounted in a suitable drilled opening provided in one side of the tubular member 16, while 33 designates a coil spring provided in a similar longitudinally drilled opening in the opposite side of the member I6 which cooperates with a plunger head 33a engaging in a suitable seat on the upper face of the spider 35 adjacent one side of the latter, for normally urging the same downwardly in one direction on its pivot pins II. The lower end of the plunger 32 accommodates a rod 320 which engages in a seat on the opposite side of the spider and is manually reciprocated to rock the same on its pivot pins l1, thereby oscillating the trueing diamond 2| carried on the free end of arm l9 connected to the spider.

l8 designates a relatively short shaft rotatably supported in a bearing member formed on the upper end of the tubular member I6, said shaft extending transversely to the upper portion of the plunger 32. This shaft carries a cam 3| adapted to engage the upper end of the plunger 32 for forcing the same downwardly to rock the spider 35 against the spring pressed plunger head 33a, and secured to the shaft I8 is a transversely extending handle |3a for facilitating the rotation of the latter to effect the aforementioned oscillation of the plunger 32 and in turn the trueing diamond 2|.

As before stated, the tubular member I6 is rotatably mounted in the cylinder 6 and in order to rotate the same, a handle 23 is suitably secured thereto adjacent the transverse shaft l6. A radial arm 26 on the member I6 cooperates with a pair of complementary stop lugs 24 and 25 secured to the upper face of the stationary flange 6a (Fig. 1) for limiting the rotary movement of the tubular member l6 and for positioning the trueing diamond 2| for each side of the grinding wheel I as will later appear.

The upper face of the flange 6a may be graduated as indicated at 28 and a pointer may be provided on the radial arm 26 for indicating the exact position of the trueing diamond.

A further stop member 23, rotatably mounted in bearing 30 on the outer periphery of the cylinder 6, cooperates with the arm 26' for defining the position of the tubular member l6 when a cylindrical surface is to be trued on a grinding wheel such as one used for grinding trapezoidal thread profiles.

In order -to observe the setting or positioning of the trueing diamond 2| against the grinding wheel I, a microscope 21 is mounted within the tubular member l6, extending downwardly therein to a point adjacent the upper edge of the spider 35. As clearly shown in Fig. 5, the spider has a central opening 34 in line with the microscope to permit of microscopic observations of the trueing tool. 36 represents a bracket suitably secured at one end to the upper face of the flange 6a and extending upwardly and inwardly, terminating at its free end in a collar which embraces the miscroscope 21 and supports the same in place in the trueing device.

Having described the construction of my invention, its operation is as follows:

Assuming that it is desired to true the grinding wheel I and that the trueing device is in inoperative position on the grinding machine as shown in Fig. 4, with the clamping member 9 locking the device in place. The clamp 9 is released by rotating the handle, thereby allowing the trueing device to be swiveled about the pivot Ill until the arm 4 comes to rest against the supporting stud l5 on the grinding machine body 3, bringing the trueing diamond 2| adjacent the grinding wheel I The clamp 9 is again tightened to lock the trueing device in place.

The knob I2 is then rotated to turn the threaded pin H in the nut I3, causing the latter to slide vertically in the hollow shaft l0 along the longitudinal slots l4. Inasmuch as the collar 5 on the trueing device supporting arm 4 is fixed to the nut I3, the former partakes of the same movement as the nut l3 to adjust the vertical position of the trueing diamond with respect to the grinding wheel.

Horizontal adjustment of the diamond in its holder 20 is accomplished by rotating the dialed knob 22 (Fig. 3).

. The tubular member I6 is then rotated by the handle 23 until arm 26 abuts the stop 25 for enabling the trueing of the left hand flank of the grinding wheel I shown in Fig. l. The shaft I8 is then operated back and forth to rock the diamond supporting arm I! on the spider about the axis thereby oscillating the diamond 2| along the flank of the wheel I, so as to dress the latter. It will be noted that this oscillating motion of the diamond follows the arc of a circle of relatively large diameter; consequently, the movement of the diamond 2| is practically rectilinear.

When the left flank of the wheel has been dressed, the handle 23 is moved in the opposite direction to bring the arm 26 in abutting engagement with the stop 2|,and the oscillating movement of the shaft I8 is repeated for dressing the right flank of the wheel, the microscope 21 permitting the operator of the machine to observe the microscopic adjustments required for a proper trueing operation of the device.

After the trueing operation is completed, the clamp 9 is released and the trueing device is swung upwardly about the pivot shaft ID to occupy the perpendicular position with respect to the grinding wheel shaft as shown in Fig. 4.

It will thus be seen that the arrangement of the pivot shaft H! on the grinding machine permits the trueing device to be quickly swung into and out of operative positions and that the particular construction of the trueing device carried by the tubular member l6, permits ready adjustment of the trueing diamond 2| without requiring the dismantling of any of the parts.

From the foregoing, it is believed that the construction and advantages of the present invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set out in the following claims.

What is claimed and desired to be secured by Letters Patent is:

1. The combination with a grinding machine for internal threads, of a profile trueing device for grinding wheels, comprising a pivot disposed at right angles to the axis of rotation of the grinding wheel and rotatably mounted on the grinding machine, a frame carrying the reversible and swivelling parts of said trueing device, means for manually operating said parts carried by said frame, said frame being slidably mounted on said pivot to advance said operable parts of the trueing device towards the grinding wheel, and bodily rotatable with said pivot to permit said operable parts to be swung from an operative position to an inoperative position, and vice versa, means for controlling the sliding movement of said frame along said pivot, and an abutment member on the grinding machine, determining the operative position of said operable parts.

2. The combination with a grinding machine for internal threads, of a profile trueing device for grinding wheels, comprising a pivot'disposed at right angles to the axis of rotation of the for manually operating said parts carried by said frame, said frame being slidably mounted on said pivot to advance said operable parts of the trueing device towards the grinding wheel, and bodily rotatable with said pivot to permit said operable parts to be swung from an operative position 10 to an imperative position, and vice versa, means for controlling the sliding movement of said frame along said pivot, an abutment member on the grinding machine, determining the operative position of said operable parts, and a trueing work observing microscope carried by said frame, independent of the reversible parts of the trueing device, the optical axis of said microscope coinciding with the axis of rotation of said reversible parts.

FERNAND TURRE'I'I'INI. 

